Irish Water staff were warned not to look out their office windows during a protest and hide the fact they worked for the hated company.

The directions came from the utility’s managing director John Tierney who ordered a lockdown of its HQ after the first bills were issued last year.

Workers were warned not to wear their ID badges in public to make sure no one found out they worked for Irish Water – voted the most distrusted firm in Ireland.

They were also told to stay away from the windows and not to look out at what was going on.

The memo, obtained by RTE under the Freedom of Information Act, was sent to all staff in the company’s Colville House headquarters in Dublin which was to be locked down for the afternoon of April 1 last year. This was the same day anti-Irish Water demonstrators gathered outside the firm’s offices on Talbot Street in the city.

It stated: “Staff must not engage with the demonstrators” and “do not display your ID in public – ensure you remember to take it off outside the building”.

The memo added: “Refrain from looking at the demonstrators from within the office. Keep away from the windows.”

It also warned workers there may be protestors still around in the street after the demonstrations.

It stated: “Please be aware that after the protest there may be protesters hanging on in the vicinity of the offices. Do not engage with protesters and please ensure you are not wearing any branding clothing and are not displaying your badge in public.”

Irish Water said it was legitimate for Mr Tierney to provide advice to staff on how best to stay safe.

The company added: “At the time this memo issued and throughout the previous year Irish Water staff were regularly subjected to ongoing treats, intimidation, verbal abuse and in some cases serious physical assault causing injury while attempting to carry out their work.”

The Anti Austerity Alliance TD revealed a huge protest is being planned for the centre of Dublin on the Saturday before the General Election.

Yesterday, the Irish Mirror revealed a source close to the Cabinet disclosed the Dail is to be dissolved next Tuesday when the election date of February 26 will be announced. This means the water charges protest will take place on February 20.